George plans on retiring in $45$ years and spend $40,000$ annually for $20$ years after the retirement. He believes the average rate of the investment over the next $65$ years is $5\%.$ a$)$ how much does he need to save each year for $45$ years to make his retirement plan possible? b$)$ if his friend puts $$30,000$ in his account to start the plan how much less does he need to save each year? does this make a big difference?